Add profile conditions, scene presets, MQTT integration, and Scenes tab

Feature 1 — Profile Conditions: time-of-day, system idle (Win32
GetLastInputInfo), and display state (GUID_CONSOLE_DISPLAY_STATE)
condition types for automatic profile activation.

Feature 2 — Scene Presets: snapshot/restore system that captures target
running states, device brightness, and profile enables. Server-side
capture with 5-step activation order. Dedicated Scenes tab with
CardSection-based card grid, command palette integration, and dashboard
quick-activate section.

Feature 3 — MQTT Integration: MQTTService singleton with aiomqtt,
MQTTLEDClient device provider for pixel output, MQTT profile condition
type with topic/payload matching, and frontend support for MQTT device
type and condition editor.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

server/src/wled_controller/storage/scene_preset.py

@@ -0,0 +1,125 @@
+"""Scene preset data models — snapshot of current system state."""
+
+from dataclasses import dataclass, field
+from datetime import datetime
+from typing import Dict, List, Optional
+
+
+@dataclass
+class TargetSnapshot:
+    """Snapshot of a single target's mutable state."""
+
+    target_id: str
+    running: bool = False
+    color_strip_source_id: str = ""
+    brightness_value_source_id: str = ""
+    fps: int = 30
+    auto_start: bool = False
+
+    def to_dict(self) -> dict:
+        return {
+            "target_id": self.target_id,
+            "running": self.running,
+            "color_strip_source_id": self.color_strip_source_id,
+            "brightness_value_source_id": self.brightness_value_source_id,
+            "fps": self.fps,
+            "auto_start": self.auto_start,
+        }
+
+    @classmethod
+    def from_dict(cls, data: dict) -> "TargetSnapshot":
+        return cls(
+            target_id=data["target_id"],
+            running=data.get("running", False),
+            color_strip_source_id=data.get("color_strip_source_id", ""),
+            brightness_value_source_id=data.get("brightness_value_source_id", ""),
+            fps=data.get("fps", 30),
+            auto_start=data.get("auto_start", False),
+        )
+
+
+@dataclass
+class DeviceBrightnessSnapshot:
+    """Snapshot of a device's software brightness."""
+
+    device_id: str
+    software_brightness: int = 255
+
+    def to_dict(self) -> dict:
+        return {
+            "device_id": self.device_id,
+            "software_brightness": self.software_brightness,
+        }
+
+    @classmethod
+    def from_dict(cls, data: dict) -> "DeviceBrightnessSnapshot":
+        return cls(
+            device_id=data["device_id"],
+            software_brightness=data.get("software_brightness", 255),
+        )
+
+
+@dataclass
+class ProfileSnapshot:
+    """Snapshot of a profile's enabled state."""
+
+    profile_id: str
+    enabled: bool = True
+
+    def to_dict(self) -> dict:
+        return {
+            "profile_id": self.profile_id,
+            "enabled": self.enabled,
+        }
+
+    @classmethod
+    def from_dict(cls, data: dict) -> "ProfileSnapshot":
+        return cls(
+            profile_id=data["profile_id"],
+            enabled=data.get("enabled", True),
+        )
+
+
+@dataclass
+class ScenePreset:
+    """A named snapshot of system state that can be restored."""
+
+    id: str
+    name: str
+    description: str = ""
+    color: str = "#4fc3f7"  # accent color for the card
+    targets: List[TargetSnapshot] = field(default_factory=list)
+    devices: List[DeviceBrightnessSnapshot] = field(default_factory=list)
+    profiles: List[ProfileSnapshot] = field(default_factory=list)
+    order: int = 0
+    created_at: datetime = field(default_factory=datetime.utcnow)
+    updated_at: datetime = field(default_factory=datetime.utcnow)
+
+    def to_dict(self) -> dict:
+        return {
+            "id": self.id,
+            "name": self.name,
+            "description": self.description,
+            "color": self.color,
+            "targets": [t.to_dict() for t in self.targets],
+            "devices": [d.to_dict() for d in self.devices],
+            "profiles": [p.to_dict() for p in self.profiles],
+            "order": self.order,
+            "created_at": self.created_at.isoformat(),
+            "updated_at": self.updated_at.isoformat(),
+        }
+
+    @classmethod
+    def from_dict(cls, data: dict) -> "ScenePreset":
+        return cls(
+            id=data["id"],
+            name=data["name"],
+            description=data.get("description", ""),
+            color=data.get("color", "#4fc3f7"),
+            targets=[TargetSnapshot.from_dict(t) for t in data.get("targets", [])],
+            devices=[DeviceBrightnessSnapshot.from_dict(d) for d in data.get("devices", [])],
+            profiles=[ProfileSnapshot.from_dict(p) for p in data.get("profiles", [])],
+            order=data.get("order", 0),
+            created_at=datetime.fromisoformat(data.get("created_at", datetime.utcnow().isoformat())),
+            updated_at=datetime.fromisoformat(data.get("updated_at", datetime.utcnow().isoformat())),
+        )